Apparatus and method for surgical fastening

ABSTRACT

Apparatus and method for applying fasteners during endoscopic surgery includes a handle portion, a triggering mechanism and a fastener application. The fastener applicator is detachable from the handle portion by virtue of a rotational locking system and may be replaced with a new fastener applicator having a fresh load of vertically stacked fasteners. The fastener may be formed around a single point on an anvil. The fastener applicator having only one actuated part in its applicator mechanism, and makes use of biased springs controlled by the position of the actuated part for the remaining part of the mechanism. Another embodiment of the invention deploys a plunger/ratchet assembly and pawl within the handle portion of the apparatus to ensure that the apparatus applicator mechanism will not reverse in the middle of a triggered application stroke. A method of applying a fastener includes the following steps: moving a fastener from a storage channel, where it has been vertically stacked, to a driving channel by a biased fastener positioning spring as a slide is retracted; advancing the slide until the slide engages the fastener in the diving channel and drives the fastener over an anvil to form the fastener. During advancement of the slide a biased stop spring is forced back into a recess thereby allowing the next fastener to move forward in the storage channel in response to the force of a biased pusher spring; retracting the slide thereby freeing the biased ejector springs to kick the formed fastener off the end of the anvil; and further retracting the slide until the fastener positioning spring is once again free to move the distal-most fastener from the storage channel into the driving channel.

FIELD OF THE INVENTION

The present invention relates generally to surgical fastening tools forfixating tissue and/or surgical materials during minimally invasivesurgery, and particularly to a surgical fastening tool having aspace-efficient, simplified fastening mechanism that permits deploymentof the tool through a minimal opening but which also maximizes thegripping area of the applied surgical fastener. More particularly, theinvention relates to a reduced diameter (5 mm) surgical fastening toolfor use in hernia repair. The tool is deployed through a reduceddiameter access port in the body to fasten a piece of surgical mesh tobody tissue using a specially formed fastener having a maximizedgripping area. The tool also has a simplified, jam-free fasteningmechanism. The present invention also relates to methods for repairing apatient's hernia through a minimized diameter access port whilemaximizing the gripping area of the surgical fastener as well as methodsfor applying surgical fasteners from a miniatured device with reducedrisk of jamming.

BACKGROUND OF THE INVENTION

During some surgical procedures, most notably hernia repair procedures,it is considered desirable by many practitioners to reinforce the muscletear or other defect with a piece of surgically implantable mesh.Physicians most often use an open-weave, sintered mesh made ofpolypropylene and hold it in place by a type of permanent fixationmethod. One common method of fixation uses metallic fasteners, such asstaples, which remain in the body permanently after the hernia repair.Medical device designers have created a number of larger-size devices tofasten tissue and/or surgical materials to tissue during minimallyinvasive surgery. According to these designs, the devices typicallycontemplate a 10-mm or wider application tool used to deploy a fastener.For example, Green et al., U.S. Pat. No. 5,356,064, col. 21, 11. 34-53,describes a device for deployment through a 12 mm trocar guide tubewherein the device stacks a set of staples at roughly a forty-fivedegree angle to the axis of the device to provide greater visibility.See Green et al. FIG. 18.

However, these tools are being judged too large for deployment accordingto the current minimally invasive techniques which are bringing the sizeof the surgical instruments and access ports down to a 5 mm diameter.Moreover, Green et al. cannot be readily scaled down because of physicallimitations caused by the generally transverse stacking of fasteners.See Green et al., FIG. 18. In addition, the design of Green et al.cannot be effectively scaled down because the fastener discharged by theapplication tool must be of sufficient scale to securely span across thedefect and/or strands of surgical mesh and efficaciously engagesufficient tissue area for adequate gripping strength. Green et al.employs a fastener forming system which unduly reduces the finished spanor width of the fastener relative to its initial width. See Green etal., FIGS. 20-21, col. 22, 11. 38-48. Thus, reduction in Green et al.'stool diameter would result in an unsatisfactory gripping area for thefinished fastener.

In addition to reducing fastener-gripping strength, smaller diametertools have other problems. For example, miniaturization of the surgicalfastening tool increases the likelihood of jamming, a common problem forminimally invasive surgical fastener tools, because the criticaltolerances for the device's moving parts would be reduced along with thesize of the instrument. Accordingly, slight changes in deployment stressand temperature can effect the mobility of the moving tool parts. TheOrigin Tacker, though of 5 mm diameter, employs a rotational actuationmechanism to deploy a helical fastener. Rotation increases thecomplexity needed for the actuation mechanism, and creates greater needto ensure reliable translation of trigger action.

What is needed is a space-efficient surgical fastening tool thatminimizes its outer diameter while maximizing the gripping area andstrength of the fastener. The fastening mechanism of the desiredsurgical fastening tool must not be complicated and should be limited toa few actuated parts to reduce the probability of jamming duringminimally invasive surgery. The device should be designed to avoiddouble firing and incomplete firing. The device should also permit forthe easy reloading of additional fasteners during extensive surgicalprocedures. The prior art devices are inadequate to meet theseobjectives.

SUMMARY OF THE INVENTION

The present invention relates to surgical fasteners, fastening tools andmethods for securing tissue and/or surgical materials during minimallyinvasive surgery. In particular, the devices of the present inventionare adapted to minimize the diameter of the surgical fastening toolwhile maximizing the area gripped by the fastener. Furthermore, thedevices of the present invention are adapted to discharge the fastenerby way of a simplified fastening mechanism with few actuated parts. Thesurgical materials to be fastened may be surgical mesh, sutures,prostheses, linings or the like. The tissue to be fastened may betissue, foreign or endogenous to the patient.

In one embodiment, the apparatus includes three major elements: afastener applicator comprising a fastener magazine; a handle portion towhich the applicator is attached; and a triggering mechanism. Thetriggering mechanism may be housed in either the fastener applicator,the handle portion or in a combination of the two. In a first aspect ofthe invention, the fastener applicator has a cantilevered anvil with across section around which the fastener may be formed at a single focalpoint when the fastener is pressed by a slide. The fastener mayinitially be M-shaped, upside-down U-shaped or other suitable shape. Ina most preferred embodiment, the anvil has a cross section that isessentially triangular and a shaping slide with a cooperating notch thatis angled to closely receive the triangular cross-section of the anvil.FIG. 1. Importantly, according to this first aspect of the invention,the single-point anvil permits the width of the slide which forms thefastener to be the same or less than the width of the stored fastenerbut without sacrificing the finished span (installed width) of theapplied fastener and the area it encloses. An anvil with a semi-circularor other round edged cross-section may also be used in combination witha round-notched slide. The space-efficiency of the slide and anvilpermits a reduction in the overall width of the fastener applicatorrelative to the width of the fastener. Traditional staple type surgicalfasteners have a slide which, when of reduced width, unacceptably reducethe span of the applied fastener to accommodate the “horns” of theslide. See FIG. 2.

In one embodiment, the apparatus is of unitary, non-detachable designwherein a fastener applicator, handle portion and a triggering mechanismare provided in a single integral unit. The fasteners may be stored inthe handle portion of the apparatus or loaded from outside the devicejust prior to use. However, according to a second aspect of theinvention, the applicator functions as a fastener magazine and isreadily removed from or locked onto the handle portion by virtue of anovel mechanism for quick attachment and detachment. The applicatorcomprises a slide actuator which operates a slide in response tooperation of the triggering mechanism to discharge fasteners. The novelmechanism locks the slide actuator into a secure, locked position withinthe detached applicator magazine so that the slide actuator is properlylocated to engage the motion-translating parts of the triggeringmechanism of the device when attached. The novel mechanism thenautomatically frees the slide actuator upon attachment of the applicatorto the handle thereby making the device ready for use. Specifically, thenovel mechanism employs an “L-shaped” pin with a recessed region thatrotates into and out of engagement with the slide actuator based on itsinteraction with pre-formed recesses in the handle of the device duringattachment and detachment. Thus, according to a preferred embodimentemploying this second aspect, when the applicator comprising a magazineof fasteners runs out of fasteners, the user may substitute a secondapplicator containing a fresh magazine. This construction also permitsthe handle portion to be sterilized and re-used.

The fastener applicator may either be of unitary construction or made ofseveral interconnecting pieces. However, in the preferred embodiment, atube of circular cross-section houses a magazine formed by thejuxtaposition of two cooperating half shells, known collectively as theinsert, each half-shell having essentially a semi-circular crosssection. The two-half shells are preferably inserted into the tubeduring manufacture. When combined, the two half-shells and the slideform the magazine or storage channel which contains a set of verticallystacked fasteners. The fastener applicator is separable from the handleportion so that the handle portion may be supplied with a new applicatorcontaining a new set of fasteners once the first set of fasteners hasbeen used.

A third aspect of the invention minimizes the possibility of jammingcaused by an improperly timed interplay between independently movingparts and also reduces the probability of jamming due to the failure ofthe trigger to actuate a key part of a multi-part actuation mechanism.Thus, in the preferred embodiment of the device employing the thirdaspect of the invention, the insert and slide form two channels: afastener storage channel and a fastener-driving channel. The fastenerstorage channel contains a plurality of vertically stacked fasteners,stacked tips to back, thereby reducing applicator width relative totools which use transversely stacked fasteners. The fasteners arecontinually urged toward the distal end of the applicator by a pusherthat is biased by a pusher spring. The fastener-driving channel furtherhouses a slide that rides in the driving channel to engage the back ofthe first fastener positioned within the driving channel. According tothe most preferred embodiment, movement of the slide drives the fasteneronto the anvil while the notch in the slide shapes the fastener over theanvil according to the first aspect of the invention.

In the preferred embodiment, the insert additionally comprises a systemof leaf springs that assist in securely positioning and advancing thefasteners one at a time during the repeated fastener applicationprocess. The action of the leaf springs is controlled by slide location.Accordingly, in the most preferred embodiment of the third aspect, theapplicator contains one actuated part, the slide, that is moved by theactive application of force generated by the triggering mechanism. Therest of the moving parts in the applicator are biased to move in acertain direction but are restrained or liberated based on the locationof the slide.

According to this most preferred embodiment, with the applicator heldagainst the target, the slide is fully advanced distally to drive thefirst fastener's tips into the target and to shape the fastener on theanvil. When the slide is subsequently retracted after shaping the firstfastener, a pair of biased ejector springs are liberated and kick theformed fastener off the end of the anvil, freeing the apparatus from thefastener. Upon further retraction of the slide, a biased fastenerpositioning spring is released and pushes the second fastener from thedistal most position in the storage channel into the driving channel.Meanwhile, a biased stop spring restrains the third fastener fromadvancing in the storage channel until the second fastener is beingadvanced in the driving channel. The third fastener is then released bythe depressed stop spring and advanced to the distal most position inthe storage channel. Fully actuating the slide to discharge the secondfastener and then fully retracting the slide positions the thirdfastener in the driving channel. This process may be repeated until eachof the fasteners in the magazine has been applied.

In the interest of further reducing the potential for jamming of theminiaturized tool during surgery, according to a fourth aspect of theinvention, the apparatus may employ a unique jam-free ratchet and pawlmechanism, housed in the handle portion, that assures complete travel ofthe slide in both directions during application of each fastener. Thisembodiment of the apparatus comprises a plunger assembly that is linkedto the slide by means of the slide actuator. Complete forward andreverse movement of the plunger assembly results in a completecorresponding motion of the slide. In the preferred embodiment, theplunger assembly reciprocates forward and backward within the body ofthe handle portion. The body of the handle has a tapered slot, adjacentto the plunger assembly, which contains a pawl. The side of the plungerassembly that is immediately adjacent to the tapered slot contains aseries of grooves which collectively form a ratchet extending for adistance approximately equal to the travel of the plunger assembly. Thelength of the pawl is longer than the perpendicular distance from thebottom of the tapered slot to the bottom of the ratchet grooves, suchthat once the pawl is engaged in the ratchet grooves, the pawl isoblique and prevents reversal of the plunger's direction of travel.

When the pawl has moved past the end of the ratchet, a wire spring urgesthe pawl to assume a position transverse to the direction of travel. Asthe plunger assembly is moved back towards its original position, thepawl again engages the ratchet but with opposite orientation.Accordingly, the pawl again prevents reverse travel of the plungerassembly until the stroke is fully completed and the pawl has clearedthe length of the ratchet. The spring then reorients the pawltransversely in preparation for the next stroke. In this way, theinvention prevents the slide, which is connected to the plunger assemblyby the slide actuator, from reversing mid-stroke and safeguards againstjamming, non-firing and misfiring.

The methods of the present invention relate to deploying a fastener withmaximized gripping area using a space-efficient deployment mechanismhaving few actuated parts. In a preferred method of the invention, ahernia repair patient is incised and fitted with a port to access thesite of the hernia. After access to the site of the hernia is achieved,the hernia is reduced and the surgical mesh is placed over the defectusing minimally invasive techniques. The surgical fastening toolapparatus is deployed through an access port and its tip pressed againstthe mesh and the tissue to be fastened. The tool is then triggered bymeans of the triggering mechanism. The fastener is then formed by theaction of the slide pressing the fastener onto the surface of the anvil.In this manner, the mesh is secured to the body tissue by the grippingstrength of the fastener.

When employing the first aspect of the invention, the method of thepresent invention generally includes the following steps: forming afastener by placing it over a single focal point anvil; pressing thefastener against the single focal point anvil using a slide having awidth that is approximately the same as or less than the width of thefastener; discharging the fastener into the tissue of the patient.

In a method that employs the second aspect of the invention, the methodof fastener application is executed within a detachable applicator whichmay be readily replaced with a second applicator containing additionalfasteners using a novel mechanism.

In a method that employs the third aspect of the invention, a fasteneris applied by the following preferred steps: the fastener is moved fromthe storage channel where it has been vertically stacked to the drivingchannel by the biased fastener positioning spring as the slide isretracted; the slide is then advanced until the slide engages thefastener in the driving channel and drives the fastener over the anvilto form the fastener. During advancement of the slide the biased stopspring is forced back into a recess in the insert thereby allowing thenext fastener to move forward in the storage channel in response to theforce of the biased pusher spring; the slide is then retracted, freeingthe biased ejector springs to kick the formed fastener off the end ofthe anvil; finally the slide is further retracted until the fastenerpositioning spring is once again is free to move the distal-mostfastener from the storage channel into the driving channel.

The present invention was developed, in part, out of recognition of theneed for a reduced diameter fastening tool which could discharge, from areduced diameter applicator, a fastener that firmly holds mesh andtissue together. Unlike a traditional staple shape where the back of thestaple lies parallel to the tissue surface into which it is deployed,the present invention teaches that a U-form wire fastener applied in theform of a diamond relative to the tissue surface has certain advantagesincluding reduction in the size of fastener needed to achieve highgripping strength. The installed span of the fastener and the areacaptured by the fastener are two useful parameters for evaluating theefficacy of a fastener. FIGS. 3a and 3 b on Table 1 demonstrate theconventional finishing of a “U” shaped staple by assuming an arbitraryinitial width of 8 mm (assuming negligible thickness of the wire andbends of 90 degrees) and monitoring these two parameters. Thetraditional “U”-shaped staple may have many finished shapes depending onthe width selected between bends in the back of the staple. In essence,the width between bends determines the finished span of the appliedstaple. See FIG. 3b. The length of the staple legs is arbitrary but thelegs should not reach too deeply into the tissue to avoid damagingunderlying structures. On the other hand, the staple must reach deeplyenough to enclose sufficient tissue to develop adequate holdingstrength.

With reference to FIG. 3b and Table 1, it is clear that, as the finishedconventional staple span is stepwise decreased, the area of theprojected rectangle formed by the finished staple goes through a maximumvalue (8). By comparison, the invention's preferred diamond shapedfastener, described in FIGS. 4b and Table 2, has a finished span of0.707×the initial width, W, and encloses a projected area double thesize of the maximum traditional design (16). Moreover, the preferreddiamond-shaped finished fastener shown in FIG. 4b, maintains a spangreater than all but the most extreme of possible finished shapes madeby the conventional process (shapes which suffer from greatly diminishedgripping area). Although the user may choose other initial widths aswell as other bend angles for the traditional method, the relativerelationship between the gripping area of the diamond fastener of thepresent invention and the conventional finished fastener remain. Whenviewed in light of the longer finished span permitted by the presentinvention, these Figures and Tables demonstrate the superior geometry ofthe finished fastener formed by the instant apparatus.

TABLE 1 CONVENTIONAL DESIGN W − 2L = SPAN L × SPAN = AREA W 2L SPAN AREA8 2 6 6 8 3 5 7 ½ 8 4 4 8 8 5 3 7 ½

TABLE 2 FASTENER FORMED BY PREFERRED EMBODIMENT OF THE INVENTION$\frac{\left( \frac{W}{2} \right)}{\left( \frac{Span}{2} \right)} = \frac{\sqrt{2}}{1}$

${SPAN} = {{\frac{1}{\sqrt{2}}\quad W} = {0.707\quad W}}$

${AREA} = \left( \frac{W}{2} \right)^{2}$

Thus, if W = 8, SPAN = 5.66 AREA = 16

To the extent the finished angle of the inserted legs relative to thesurface plane of the tissue is related to the fastener's strength, afastener's legs which finish parallel to the tissue surface are superiorto those which finish perpendicular to tissue. Accordingly, in analternate embodiment, described in FIG. 5a and 5 b and Table 3, thefastener may be initially formed with an upwardly concave back of anarbitrary angle and with legs which are initially parallel,approximating the capital letter “M”. FIG. 5a. In the embodiment shown,the angle of the concave back is greater than ninety-degrees. Duringformation of the fastener the central bend is reversed to allow the legsto finish more parallel to the tissue surface. FIG. 5b. According tothis embodiment, the length of the finished span remains essentially thesame as the finished span shown in FIG. 4a, 4 b but the projected areagripped by the fastener is reduced.

TABLE 3 SPAN ≧ .707 W AREA = ½(>W/2)² ≧ 8

To the extent finished span is chosen as the key parameter for achievingholding strength, the preform shown in 5 a may be formed over the anvilby partial application of the slide such that the back of the fastenerbecomes essentially flat, and parallel with the tissue surface intowhich the fastener in being deployed. In this variation, the slide isnot pushed all the way down such that the back ends up more or lessstraight and the legs angled. The span and area calculations then becomethose for the finished shape.

The gripping area is reduced to a value that is still greater than orequal to the maximum area gripped by the conventionally processedU-shaped design described in FIG. 3b. Importantly, the finished span ofthe conventionally processed U-shaped design is substantially less (0.5W=4) compared to the finished span of the concave back fastener (0.707W=5.66). Thus, it is clear that with respect to the length of thefinished span and the gripping area of the fastener, triangular finishedfastener designs, shown in FIG. 5b, are also superior to conventionallyprocessed designs. This recognition is particularly important when thegoal is to miniaturize a surgical fastening tool for use in minimallyinvasive surgery.

Miniaturization of a fastener tool places a premium on the grippingefficiency of the fastener relative to the space available for itsdeployment within the small diameter of the applicator. Assuming thatthe applicator of a surgical fastening tool comprises a tubular housing,a slide that forms the U-shaped fastener with two bends in the back musthave “horns” and be wider than the finished span thereby wasting tooldiameter.

Thus, as a practical matter, the conventional mechanism necessarilyresults in a fastener with a smaller finished span for a given tooldiameter. See FIG. 2. In contrast, the finished diamond and triangularfasteners shown in FIGS. 1, 4 b and 5 b, do not need the slide to bewider than the finished span of the fastener.

Using the fastener and anvil configurations of FIGS. 4 and 5, the tooldesign need not sacrifice the length of the finished span to accommodatethe fastener forming apparatus itself. Moreover, the disclosed inventionrequires less force to deploy the fastener because only one bend isformed during deployment rather than two bends as with the conventionaldesign. This reduction in force is a significant advantage for aminiaturized device whose miniaturized parts are relatively weak and mayfail under repeated stress.

The present invention was also developed in part to solve other problemsassociated with miniaturization of fastener devices, such as jamming,non-firing and misfiring. Thus, the invention contemplates that thedeployment mechanism of the device has few mechanically actuated partsbecause the critical tolerances for such actuated parts are reduced inthe miniaturization process. Moreover, surgical fastening tools are attimes roughly handled in a hospital setting and may undergo significantabuse during sterilization. This can cause the internal uncoupling ofactuated parts or other damage not visible from the surface of the tool,only to be discovered during use of the device. Thus, a feature limitingthe number of actuated parts leads to a sturdier, more reliable device.This feature also simplifies the manufacturing process.

Finally, the invention was motivated by the knowledge thatminiaturization of the surgical fastening tool may cause the tool tocarry fewer fasteners than may be needed for a particular surgicalprocedure. Thus, according to another aspect of the invention, thefastening tool comprises an interchangeable fastener magazine.

It is a general object of the present invention to eliminate or reducethe problems associated with jamming of small diameter surgicalfastening tools.

It is another object of the present invention to reduce the number ofactuated parts in the deployment mechanism of the tool so as to reducethe number of critical tolerances between coupled parts and reduce therisk of decoupling or other malfunction. For example, in one embodimentof the invention, the insert of the fastener applicator incorporatesonly one actuated component.

Another object of the present invention is to maximize the gripping areaof the fastener while reducing the diameter of the applicator of thesurgical fastening tool. Because of the nature of surgical repair, it isundesirable to have to refasten the surgical material after surgery iscompleted. Accordingly, the fasteners should form a strong link betweenthe fastened materials and/or tissue so that the materials stay in placeduring post-surgical patient activity. Secure fasteners have previouslyrequired larger diameter fastening tools which are incompatible with thenew, reduced-diameter, minimally invasive surgery techniques.

It is a further object of the invention to provide a surgical fasteningtool that is economical and convenient for fastening hernia mesh and thelike during minimally invasive surgery.

It is a further object of the invention to provide a surgical fasteningtool with an interchangeable magazine portion that permits fast andreliable introduction of new fasteners into the tool.

It is further object of the invention to provide a disposable,detachable applicator which contains a complete fastening mechanism andset of fasteners, thereby permitting both the fast, convenientreplacement of fasteners during surgery as well as the reuse of thehandle and trigger portions.

It is a further object of the invention to ensure complete travel of thetool's fastening mechanism in each direction to prevent against partialfiring, empty firing and jamming during use.

As for the methods of the invention, one object of the invention is toprovide a fastening mechanism that is both compatible with minimallyinvasive surgery techniques using reduced port diameters (5 mm is thenewest standard in the field of minimally invasive surgery) and whichprovides fasteners that maximally grip the area of tissue and material.

It is a further object of the invention to provide a method of applyinga fastener during minimally invasive surgery that includes easyreplacement of spent fastener magazines.

It is a further object of the invention to provide a reliable method forfastener application during minimally invasive surgery that avoidsjamming, non-firing and misfiring.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference is made to a brief description of the drawings, which areintended to illustrate surgical fastening tools for use herein. Thedrawings and detailed description which follow are intended to be merelyillustrative and are not intended to limit the scope of the invention asset forth in the appended claims.

FIG. 1 is a schematic front view of an embodiment of the preferredfastener, space-efficient shaping slide and anvil of the presentinvention.

FIG. 2 is a schematic front view of a traditional staple with itsshape-forming slide about to form the staple on a rectangular anvil.

FIG. 3a is a schematic front view of a traditional U-shaped staple priorto application of a conventional shaping slide.

FIG. 3b is a schematic front view of a finished traditional U-shapedstaple after application of a conventional shaping slide.

FIG. 4a is a schematic front view of an embodiment of the fastener ofthe present invention prior to application of the shaping slide.

FIG. 4b is a schematic front view of an embodiment of the fastener ofthe present invention after application of an embodiment of the shapingslide of the present invention.

FIG. 5a is a schematic front view of alternate embodiment of thefastener of the present invention prior to application of an embodimentof the shaping slide of the present invention.

FIG. 5b is a schematic front view of the alternate embodiment of thefastener of the present invention after application of an embodiment ofthe shaping slide of the present invention.

FIG. 5c is a schematic front view of the alternate embodiment of thefastener of the present invention after partial application of theshaping slide of the present invention.

FIG. 6 is a longitudinal view of one embodiment of the surgicalfastening tool that includes a handle portion, a trigger portion and anapplicator.

FIG. 7 is a cross-section of the applicator of one embodiment of thesurgical fastening tool with the slide fully extended distally.

FIG. 8 is the same cross-section of the applicator of the embodiment ofthe surgical fastening tool shown in FIG. 7 but with the slide in thefully retracted position.

FIG. 9 is a three-dimensional rendering of the first half-shell andfastener positioning spring of the applicator shown in cross-sectionalperspective in FIGS. 7 and 8.

FIG. 10 is a three-dimensional rendering of the second half-shell of theapplicator and stop spring shown in cross-sectional perspective in FIGS.7 and 8, with the first half shell poised above.

FIG. 11 is a front view of the slide, slide actuator and anvil rotatedninety-degrees from their depiction in FIGS. 7 and 8.

FIG. 12a is a schematic front view of the preferred slide and fastenerof the present invention prior to forming of the fastener.

FIG. 12b is a schematic front view of the preferred slide and fastenerof the present invention after the forming of the fastener.

FIG. 12c is a three-dimensional rendering of the preferred slide of thepresent invention.

FIG. 13 is a cross-sectional view of the handle portion and triggerportion of a preferred embodiment of the surgical fastening tool.

FIG. 14 is a three-dimensional cross-sectional perspective view of apreferred embodiment of the fastening tool wherein the applicator isreadily detachable from the body portion.

FIG. 15a is a three-dimensional perspective view of the proximal end ofthe slide actuator and “L”-shaped pin with the pin in the unlockedposition.

FIG. 15b is an exploded view of the handle portion revealing the camsurfaces and recessed regions which provide the mechanism for attachingthe applicator to the handle portion as well as the slide actuator lockand release mechanism.

FIG. 16 is a cross-section of the preferred handle portion of thepresent invention wherein the handle portion contains a tapered slotthat houses a pawl.

FIG. 17 is a three-dimensional rendering of the preferred plungerassembly of the present invention showing a pawl standing clear of theratchet portion of the plunger assembly following completion of astroke.

FIG. 18 is a time-sequenced frontal view of the plunger and pawlmechanism undergoing one complete cycle of application and retraction.

FIG. 19 is a three-dimensional perspective view of the pawl and wirespring.

DETAILED DESCRIPTION OF THE INVENTION

Referring more particularly to the drawings, FIG. 6 shows one embodimentof the surgical fastening tool. The surgical fastening tool comprises ahandle portion 10 an applicator 20 and a trigger portion 30. FIG. 7shows a cut-away cross-section of a preferred embodiment of theapplicator portion of the device. According to the preferred embodiment,the applicator comprises a tubular housing 40 having an insert containedwithin. Although the insert could be made as a single unit or even bemanufactured out of a single piece that forms the tubular housing, theinsert is preferably made from two cooperating half-shells which areinserted into the tubular housing. The half-shells preferably have abeveled outer edge which permits crimping of the distal most end of thetubular housing to secure the insert. In the preferred embodiment, thefirst half-shell 50 has a rounded side 52 which abuts the tubularhousing 40 and a flat side 54 that has recessed region 70 whose surfaceforms one the walls of the fastener storage channel containing fasteners80. Above the fasteners 80 sits a pusher 82, which rides in the fastenerstorage channel. The pusher 82 continuously exerts a downward pressureon the vertically stacked fasteners 80 by virtue of a biased pusherspring 84.

Recessed region 70 gradually rises to the diametrical plane of flat side54 (diametrical relative to the tube circumference on flat side 54) byvirtue of a slanted ramp 72. A fastener positioning spring 60 attachedto and flush with the recessed portion 70 of flat side 54 of the firsthalf-shell 50 is biased to extend beyond both the recessed region 70 ofthe flat side 54 and the most prominent plane of the flat side 54. Thespring 60 is capable of being completely contained within a slot 90 inthe first half-shell. Finally, the first half-shell 50 has a cut-awayregion 92 at the distal end of the applicator to permit ejection of thefastener.

A perspective view of the first half-shell 50 is shown in FIG. 9. Thediametrical plane of flat side 54 appears uppermost in the drawing. Thisview shows that in a preferred embodiment the cut-away region 92 has twofurther recessed regions 94 a and 94 b.

A second half-shell 100, shown in FIG. 10, has a flat side 102 and arounded side 104. Flat side 102 has a recessed area 110 whose planeforms one of the walls of the driving channel in which slide 120 rides.The distal end of second half-shell 100 comprises an anvil 130 with atriangular cross-section. Anvil 130 is a cantilever that extends beyondthe recessed area 110 across the driving channel and into cut-awayregion 92 on the first half-shell of the insert. On either side of theanvil 130 are slot regions 140 a and 140 b, shown in the cross-sectionof FIG. 10, which house ejector springs 150 a and 150 b (not shown).Ejector springs 150 a and 150 b are, at their proximal end, attached toround side 104 and are flush with its outer circumference. However, thedistal parts of the ejector springs 150 a and 150 b are biased suchthat, when unrestrained, the springs extend beyond the anvil 130 andenter the further recessed regions 94 a and 94 b of first half-shell 50.Alternatively, the cutaway region 92 may fully accommodate the ejectorsprings 150 a and 150 b without the need for recessed regions 94 a and94 b. Spring 150 b is shown in phantom line in FIG. 7.

With reference to FIG. 7 the recessed region 110 of the secondhalf-shell has a slotted region 160 that houses stop spring 170. Stopspring 170 is secured nearby in a radial hole 171 in the secondhalf-shell 100. Stop spring 170 is also biased such that, whenunrestrained, it extends out beyond recessed area 110 through slottedregion 200 in slide 120 and beyond joint diametrical planes of theinserts 50 and 100 to engage the fasteners.

Slide 120, shown in detail in FIG. 11, along with slide actuator 190 arethe only actuated parts in the preferred embodiment of the applicator20. According to the preferred embodiment, slide 120 alternatelyrestrains and releases all the biased moving parts of the applicator 20.Slide 120 is connected to slide actuator 190 within tube 40 at a pointbeyond the proximal end of both half-shells, 50 and 100. Alternatively,for an apparatus which does not have a detachable applicator, slide 120may extend all the way into the handle portion, thus reducing the numberof actuated parts in the applicator to one.

In the preferred embodiment slide 120 has a slotted region 200, whichalternately restrains and releases stop spring 170 by allowing it toprotrude through the slide. Slide 120 forms one wall of the storagechannel created by the recessed region 70 in first half-shell 50.

The distal end of the slide 120, in the preferred embodiment, is forkedand beveled to cooperate with triangular shaped anvil 130, as shown inFIG. 11, 12 a, 12 b and 12 c. This feature permits the slide width to beequal to or less than the fastener width. In the most preferredembodiment, the width of the slide 120, as well as that of the storagechannel created by the surfaces of recessed region 70 and slide 120,extends almost the entire diameter of the joined half-shells, 50 and100.

The preferred method of applying the fastener is demonstrated by FIGS. 7and 8. FIG. 8 shows that when the slide 120 is fully retracted, thefastener positioning spring 60 urges the distal-most vertically-stackedfastener 80 from the storage channel to the driving channel locateddistal to slide 120. As the slide 120 is advanced in the driving channelby virtue of the slide actuator 190, the tines of the forked bottom ofslide 120, shown in FIG. 12a, exert a downward pressure on the firstfastener 80. As the slide 120 advances, it lifts the stop spring 170 outof slotted region 200 of the slide 120 (not shown), out of the storagechannel where it previously restrained the second of the stackedfasteners and into recessed region 160 of the second half-shell piece100. The second of the stacked fasteners is thereby released by stopspring 170 and advanced by the pusher 82 which is forward biased bypusher spring 84 (not shown in FIG. 8). The second fastener thusadvances to the distal-most position in the storage channel, a positionpreviously occupied by the first fastener.

As demonstrated by FIG. 7, advancement of the slide as described abovealso blocks fastener egress from the storage channel along its length,thereby preventing the next fastener from prematurely entering thedriving channel. Additional advancement of the slide 120 pushes ejectorsprings 150 a and 150 b back into slotted regions 140 a and 140 b (notshown). This permits the foremost fastener to rest on the anvil 130until the fully advanced slide shapes the fastener on the anvil, asdemonstrated in FIGS. 7, 12 a and 12 b.

Once the fastener is formed on the anvil 130 and the toes of thefastener are securely in the tissue, the slide 120 is retracted suchthat biased ejector springs 150 a and 150 b are free to extend past theend of the anvil and kick the fastener off of the cantilevered anvil. Asa result the applicator is freed and the fastener remains securelyattached to the tissue and/or surgical material.

According to the preferred method, the slide 120 is subsequentlyretracted until the stop spring 170 passes through the slotted region200 of the slide and hooks underneath a third fastener in the storagechannel thereby preventing the third fastener's further advancement.Upon further retraction of the slide 120, the biased fastenerpositioning spring 60 is freed, thereby pushing the second fastener intothe driving channel space vacated by slide 120.

Although the foregoing sequence of steps is preferred, in an alternateexecution of the method, the sequence of steps triggered by the slide'saction may involve simultaneous execution, or may even be reversed, aslong as the method achieves the objectives of not permitting twofasteners into the driving channel at the same time, not permittingempty firing and not permitting the device to jam.

With respect to the handle portion 10 and the trigger portion 30, theinvention contemplates that there are many ways to fashion theseelements. However, to further the goals of minimal jamming and misfiringby the miniaturized tool, the invention teaches a preferred handleportion and trigger portion, shown separately in FIG. 13, that workconsistently and reliably with the preferred applicator embodiment andother applicator designs. In a preferred embodiment, the handle portion10 consists of a pistol grip portion 12 and a barrel portion 14. Thetrigger portion 30 of the preferred embodiment comprises a trigger 302having a cam follower 304 which fits within the handle portion 10 and ispivotally attached at pivot 303 to the pistol grip portion 12 and biasedby spring 306. The cam follower 304 engages a cam 308 which extends froma cooperating hinged lever 310 that resides within the pistol gripportion 12. The hinged lever 310 is pivotally attached near the butt ofthe pistol grip portion 12 and extends through the handle portion 10into the barrel portion 14. The hinged lever 310 has at its upper end afork 312 whose crotch is aligned with the axis of the tubular housing 40of applicator 20 (not shown). The fork 312 is biased away from theapplicator 20 (not shown) by fork biasing spring 314. The fork 312connects to a plunger/ratchet assembly 316 which has a distal andproximal end. The proximal end of plunger/ratchet assembly 316 isgrooved to accept the fork 312. As shown in FIG. 14, the distal end ofplunger/ratchet assembly 316 connects to slide actuator 190 which inturn connects to slide 120 (not shown) within the applicator 20. Thetrigger portion 30 is contained in a recess of handle portion 10 whichmay consist of two halves fitted together, such as 10 a and 10 b.

The preferred embodiment functions as follows: squeezing trigger 302causes lever fork 312 to be thrust toward the distal end of the barrelportion 14 by the response of the cam 308 to action of the cam follower304. Release of the trigger 302 causes fork 312 to retract to itsoriginal position by virtue of a fork biasing spring 314 and triggerbiasing spring 306 which returns these same elements back to theirresting positions.

The limited number of fasteners deployable within a miniaturized devicemay create the need for easy, reliable reloading during extensivesurgical procedures. Many hospitals desire to have a reusable portion ofthe fastener applicator tool. FIG. 14 shows a preferred embodiment inwhich an applicator 20 containing stacked fasteners 80 (not shown) thatis readily detachable from body portion 10 by rotating the applicator 20and axially moving it away from the handle portion 10. A new applicatoris readily attached in the reverse manner. The applicator 20 thusfunctions as a fastener magazine and is replaced every time a new supplyof fasteners is required.

In the preferred embodiment of this aspect of the invention, slideactuator 190 is notched at its proximal end to accept the drive pin 318present on the distal end of the plunger/ratchet assembly 316. However,because the slide actuator 190 would otherwise freely move withinapplicator 20 when the applicator 20 is not attached to the handleportion 10, the slide actuator 190 is locked into place by virtue of an“L”-shaped pin 320 having a flat spot on its shank.

FIG. 15a illustrates a simplified close-up of this locking feature. Theleg of “L”-shaped pin 320 passes through hub 321 (not shown) and engagesa notched region 330 of slide actuator 190. When the leg portion of“L”-shaped pin 320 is parallel to the bore of the tubular housing 40, asin FIG. 14, the shank engages notched region 330 of the slide actuator190 and the slide actuator is locked. However, when the external portionof pin 320 is transverse to the bore of the tubular housing 40, as inFIG. 15a, the flat portion of the pin shank is free of notches 330 andas a result the actuator 190 is free to slide axially in response toactuation by the handle and trigger portions. As shown in FIG. 14, thepin 320 and the proximal end of the slide actuator 190 are preferablyprotected by a skirt 340 to prevent any inadvertent change in theposition of the “L”-shaped pin 320 during handling of the actuator. Theskirt 340 also protects against damage to the proximal end of the slideactuator 190. According to this feature, the distal end of the barrelportion 14 of handle portion 10 of the fastener applicator tool isreceived within the skirt 340 and connected to the slide actuator 190within the skirt.

With reference to FIG. 14, which shows detail of the applicator magazineattachment to the handle portion, the handle portion 10 is made of twobody portions, 10 a and 10 b, which fit together, house the trigger 302,fork lever 312 and plunger/ratchet assembly 316. According to thisapplicator magazine embodiment, the handle portion 10 comprises a socketat its distal end that is shaped to receive the proximal end hub 321 ofapplicator 20. The plunger/ratchet assembly 316 is fitted with a drivepin 318 for engagement with slide actuator 190 and the proximal end ofthe slide actuator 190 is notched to receive the drive pin 318. In lieuof a skirt 340, applicator 20 may simply have a grip disposed about itscircumference that allows the user to grip the applicator 20 duringassembly with the handle portion 10.

In the preferred applicator magazine attachment mechanism shown in FIG.15b, the applicator 20 is inserted into the handle portion 10, comprisedof two handle halves 10 a and 10 b, by sliding its proximal end into thesocket of the handle portion 10, and rotating the applicator. The act ofinserting the proximal end of the applicator 20 into the distal end ofthe handle portion 10 and rotating it serves several purposes: first, itlocks the applicator 20 onto the handle body 10; second, the rotationcauses the “L”-shaped pin 320 to rotate in response to a cam surface 328thereby freeing the slide actuator 190 from its locked position into aready position; third, rotation causes the notch in the slide actuator190 to engage the drive pin 318 on the plunger/ratchet assembly 316; andfourth, detent structure 327 engages the shank of the “L”-shaped pin,preventing inadvertent rotation in use. FIG. 15b shows the detail of themechanism for connecting the applicator to the handle. The two handlehalves 10 a and 10 b comprising relief grooves 323, 324, 325 and 326 andcam surfaces 328 and 329, engage the proximal end of the actuator hub321 for the purpose of releasably holding the applicator to theassembled handle. In FIG. 15b, the handle halves are shown separated andopened out in juxtaposition to illustrate their features. Also shown isthe actuator hub 321 with slide actuator 190 locked in place by the“L”-shaped pin. The embodiment shown here does not incorporate a skirtas in FIG. 14. On insertion of the hub into the handle bore that iscreated by the junction of handle halves 10 a and 10 b, the reliefgrooves 323, 324, 325 and 326 form grooves of different depths such thatthe hub may only be assembled in one position because of the profile ofthe “L”-shaped pin 320. After full insertion, clockwise rotation pressesthe arm of the “L”-shaped pin against cam surface 328 and turns the arm90° to the axis of the hub 321. Rotation is continued until the shank ofthe “L”-shaped pin passes past the detent 327 at the end of the groovein the handle to lock the actuator in position. The actuator is thuslocked in place ready for use, and cannot inadvertently back-rotate anduncouple. After insertion, the device is ready for operation as if itwere a tool of unitary construction. Reversing this rotation step freesthe slide actuator 190 from drive pin 318, and on withdrawal, cam 329rotates the leg of the “L”-shape pin back into engagement with thenotched region of the slide actuator 190 on withdrawal, thereby lockingthe actuator, and disconnects the applicator 20 from the handle portion10. If a skirt is incorporated into this attachment apparatus as in FIG.14, it may be integral with or attached to the hub 321. If the apparatusis of unitary construction, the releasable attachment mechanism may beeliminated and the cooperating elements are non-detachably joined.

According to another aspect of the invention, the preferred embodimentincludes a ratchet and pawl system designed to guarantee complete,irreversible travel of the applicator mechanism during each stroke ofthe application cycle. This aspect of the invention, shown in FIGS. 16and 17, contemplates that the plunger/ratchet assembly 316 reciprocatesbackward and forward within the barrel portion 14 of the handle portion10. A tapered slot 400 is provided in the handle portion 10 and a pawl402 is placed within that tapered slot. A wire pawl spring 406 extendsbetween posts 404 a and 404 b. The pawl spring 406 urges the pawl 402into a perpendicular position relative to the direction of plungertravel by means of a slot in the pawl. The side of the plunger/ratchetassembly 316 that faces pawl 402 has a series of grooves forming aratchet 408 which extends approximately as far as the extent of travelof the plunger/ratchet assembly 316 within the handle portion 10. Thelength of pawl 402 is somewhat greater than the distance between thebottom of the tapered groove and the bottom of the ratchet grooves. Thepawl 402 is thus trapped at an oblique angle between the slot 400 andthe ratchet 408 during plunger travel.

FIG. 18 shows the complete fastener application cycle with reference tothe plunger/ratchet assembly 316. Once the plunger travel is initiatedand the pawl is engaged in the ratchet, any attempt to reverse directioncauses the pawl 402 to jam between the slot 400 and the ratchet 408thereby immediately stopping counter-travel. The plunger/ratchetassembly thus can only move in the initial stroke direction until thepawl travels past the end of the ratchet 408 and out of engagement withthe plunger/ratchet assembly. At that point, the wire pawl spring 406causes the pawl 402 to assume a position that is perpendicular to theratchet 408. The initiation of travel of the plunger/ratchet assembly inthe opposite direction (the return stroke) again places the pawl 402into engagement with the ratchet at an angle, but this time the pawl isoriented in the opposite sense. Thus, the pawl's orientation makesmid-stroke reversal impossible once again until travel is complete andthe pawl clears the other end of the ratchet completing the cycle. Byadjusting the geometry of the ratchet and pawl as well as providingtravel stops for the plunger assembly, the device eliminates mid-strokereversals and thereby helps prevent jamming, non-firing and misfiring.FIG. 19 shows in detail the spring 406 deployed in the slot of the pawl402 so as to orient the pawl.

While particular endoscopic devices and methods have been described forapplying fasteners, once this description is known, it will be apparentto those of ordinary skill in the art that other embodiments andalternative steps are also possible without departing from the spiritand scope of the invention. Moreover, it will be apparent that certainfeatures of each embodiment can be used in combination with devicesillustrated in other embodiments. For example, the four various aspectsof the invention may be mixed and matched to create a variety ofsurgical fastening devices with varying features. Accordingly, the abovedescription should be construed as illustrative, and not in a limitingsense, the scope of the invention being defined by the following claims.

What is claimed is:
 1. A fastening apparatus for use in endoscopicsurgery comprising: a) a handle portion; b) a triggering mechanismpositioned at least partially within the handle portion; and c) afastener applicator connected to said handle portion, said fastenerapplicator comprising a shaping slide having a cooperating notch,wherein said notch has as its widest width a distance essentially equalto the width of the shaping slide, and anvil having a generallytriangular cross-section.
 2. The apparatus of claim 1 wherein thecooperating notch is angled to closely receive said anvil.
 3. Thefastening apparatus of claim 1 wherein the anvil defines a singlefastener-forming point.
 4. The apparatus of claim 1 wherein the fastenerapplicator further comprises a plurality of fasteners.
 5. The apparatusof claim 1 wherein the fastener applicator is separable from said handleportion.
 6. The apparatus of claim 1 wherein the fastener applicatorcomprises a plurality of vertically stacked fasteners.
 7. The apparatusof claim 1 wherein the fastener applicator is formed of two cooperatinghalf-shells.
 8. The apparatus of claim 1 wherein the fastener applicatordefines a longitudinal storage channel and a longitudinal drivingchannel.
 9. The apparatus of claim 8 wherein said shaping slidealternately covers and uncovers an opening from the storage channel tothe driving channel.
 10. The apparatus of claim 1 wherein the fastenerapplicator further comprises a slide actuator operatively connected tosaid slide.
 11. The apparatus of claim 10 wherein said slide actuator islockable by engagement of a pin that alternately engages and disengagessaid slide actuator in response to said pin's interaction with recessesin the handle portion.
 12. The apparatus of claim 1 wherein the fastenerapplicator further comprises a plurality of biased springs forpositioning at least one fastener in response to a position of theshaping slide.
 13. The apparatus of claim 12 wherein at least one ofsaid biased springs is a fastener stop spring.
 14. The apparatus ofclaim 12 wherein at least one of said biased springs is an ejectorspring.
 15. A fastening apparatus for use in endoscopic surgerycomprising: a) a handle portion, b) a triggering mechanism positioned atleast partially within the handle portion; and c) a fastener applicatorcomprising an anvil having a substantially triangular cross-section, anda shaping slide with a cooperating notch that is angled to closelyreceive said anvil.
 16. A method of fastening a surgical fastener inendoscopic surgery comprising the steps of: placing a fastenerapplicator in close proximity with a surgical site; retracting a slidewithin a driving channel of the fastener applicator, moving a surgicalfastener from a storage channel within the fastener applicator to thedriving channel by a surgical fastener positioning mechanism as theslide is retracted; advancing the slide until the slide engages thesurgical fastener in the driving channel and drives the surgicalfastener against an anvil to form the surgical fastener; forcing a stopmechanism, during advancement of the slide, back into a recess therebyallowing another surgical fastener to move forward in the storagechannel in response to a force of a fastener pusher; retracting theslide; and ejecting the formed surgical fastener off of the anvil.